The invention is directed to an apparatus and method for the processing of polyvinyl acetate for use in chewing gum and chewing gum bases.
There are several systems known today for producing chewing gum bases and the final chewing gum products. Typically, a chewing gum base is made separately from the final chewing gum, although there are some systems which are capable of producing a final chewing gum product in one continuous process.
In general, a chewing gum composition typically comprises a water-soluble bulk portion, a water-insoluble chewing gum base portion, and typically water-insoluble flavoring agents. The insoluble gum base generally comprises elastomers, elastomer solvent, fillers, resins, polyvinyl acetate (PVA), fats, plasticizers, waxes, emulsifiers, and other miscellaneous ingredients. The water-soluble portion dissipates with a portion of the flavoring agent over a period of time during chewing. The gum base portion is retained in the mouth throughout the time that the product chewed.
Numerous chewing gums and chewing gum bases are produced using a batch method. Sigma blade batch mixers are typically used for this conventional process. The gum base ingredients are added either separately or simultaneously into the batch mixer and the material is then melted and mixed over time. After the gum base is processed, the molten gum base batch is emptied into coated or lined pans, or pumped to other equipment such as holding tanks or a filling device, then extruded or cast into shapes, and allowed to cool and solidify, before being ready for use in chewing gum.
The final chewing gum product can also be processed using a batch method. A portion of the gum base, together with softeners and bulking agents, such as sugars or sugar alcohols, are added to the mixer. Later, flavorings such as flavored oils and/or spraydried flavors, sweeteners or acids are added while mixing is continued until a homogeneous mass is achieved. Delivery systems of this type are shown, for example, in U.S. Pat. Nos. 4,816,265, 5,000,965 and 5,057,328. The chewing gum mass is then cooled and later rolled, scored, and wrapped into the final product.
Continuous extrusion machines can also be used for producing chewing gum bases or the final chewing gum products, or both. The use of continuous extruders to make a final chewing gum product are shown, for example, in U.S. Pat. No. 5,135,760 to Degady et al.; U.S. Pat. No. 5,045,325 to Lesko et al.; and U.S. Pat. No. 4,555,407 to Kramer et al. Processes known in the art for continuously producing a chewing gum base with the use of a continuous extrusion machine are shown, for example, in U.S. Pat. Nos. 5,419,919 and 5,486,366, both to Song et al.
The continuous gum base and chewing gum product processes disclosed in these patents typically utilize a continuous extrusion machine, such as a twin-screw extruder. These extruders typically have several different feed inlets where the ingredients are added. The elongated screws inside the barrels of the extruders are equipped with different types of elements. Continuous extrusion machines which can be used for producing chewing gum bases and final chewing gum products include extruders from Togum, Baker Perkins, Werner and Pfleiderer Corp., Japan Steel Works, Leistriztz, WLS and Buss Mfg. Co.
Whether a batch-type process or a continuous extruder-type process is used to produce the chewing gum and gum base products, it is important to provide the various ingredients for these products in the best form and condition. This improves the speed and efficiency of the final processing, and also improves the uniformity and consistency of the final product. In this regard, ingredients such as fillers, elastomers, plasticizers, resins, PVA, oils, waxes, and the like, often require special handling or preparation prior to being included in the batch or extrusion process.
Preparation of the ingredients is especially important where continuous extrusion processing is utilized. The ingredients applied to the continuous extrusion apparatus are preferably provided in the optimum size, shape, condition (liquid, solid, etc.), and temperature for ease of insertion and intermixing with the other ingredients in the extruder.
In order to achieve a homogeneous phase gum base or gum product wherein a proper resiliency is constant throughout and the product is free from lumps and other irregularities, it is necessary to provide the ingredients which are compatible with one another and are as dispersed and distributed as much as possible in the materials being processed. Processing and environmental conditions, such as temperature, humidity, and the like, must also be considered and taken into account in preparing a useable gum or gum base product.
Several of the ingredients typically used in chewing gum and gum base products, such as elastomers, solid resins, plasticizers and elastomeric solvents, are often difficult to handle and process. One material commonly used in the chewing gum products is polyvinylacetate (PVA). This material can be used as a resin, plasticizer or elastomer solvent for the gum and gum base products. A plasticizer is often also referred to as a softener.
PVA-material is typically provided in solid form, namely as individual wafers, pastilles, pellets or small pieces packed in a bag or other container. That material, which is tacky and thus difficult to process with automatic equipment, typically needs to be inserted into a continuous extrusion machine in individual small pieces. Also, it is often necessary to insert PVA and similar materials through a side feeder into the main extruder. In this manner, the material can be inserted in solid small particle form at the appropriate point or stage of the extrusion process. Side feeders of this type are available, for example, from Buss Mfg. Co., Werner and Pfleiderer Corp. and Baker Perkins.
Further, when using a side feeder, it is often difficult to clean or maintain the feeder apparatus without physically moving the entire apparatus away from the main extruder.
It is a general object of the present invention to provide an improved method and apparatus for the production of chewing gum products and gum base products. It is also an object of the present invention to provide improved apparatus and methods for preparation of certain chewing gum and gum base ingredients prior to processing in order to facilitate improved processing and an improved final product.
It is still another object of the present invention to provide a method and apparatus for continuously preparing chewing gum bases and products which have a consistent and uniform composition. It is another object of the present invention to provide an improved process and apparatus for supplying chewing gum base and chewing gum product ingredients, particularly PVA, to a continuous extruder in an optimum condition and form in order to provide a consistent and uniform final product.
It is still another object of the present invention to provide an improved adapter mechanism for operationally connecting a side feeder extrusion apparatus to a main extrusion apparatus.
These and other objects, benefits, and advantages are met by the following description of a preferred form of the invention.
The present invention provides an improved apparatus and process for producing a gum base and the final chewing gum product. A novel process and apparatus and system are used to handle and process several of the hard-to-handle ingredients for a continuous gum making system. These ingredients include, for example, resins, plasticizers and elastomeric solvents, including, in particular, polyvinylacetate (PVA).
In accordance with the present invention, a low-speed lump breaking apparatus is utilized to break up and divide the PVA or like material into small individual pieces. The lump breaker has a rotating blade which separates the particles into their original individual piece or wafer-like form. The removed material is pneumatically conveyed to a feeding system for a side feeder to the main extruder. The material is stripped from the pneumatic conveying air by a cyclone receiver and fed by gravity into a holding receiver. The holding receiver acts as a holding bin which releases the material through a computer control valve and a volumetric loss-in-weight feeder.
A magnetic metal detector is used to remove any metallic impurities from the material. The material is inserted into the barrel of the main extruder and intermixed and intermelted with the molten mass to form the final gum base or chewing gum product.
Throughout the process in accordance with the present invention, the material is kept at a low temperature and is physically and manually handled as little as possible. In this manner, the material, such as PVA, remains in a solid, unmelted condition and is eventually conveyed into the main extruder in the desired condition for further processing.
An adapter mechanism is used to connect and join together the side feeder with the main extruder. The adapter allows the elongated shafts in the side feeder to be retracted and maintained without separation of the two extruders.
With the present invention, a better quality final product is secured. The extrusion process is more consistent since the rates of speed and temperatures in the various stages of the extruder and the ingredients are kept to their optimum level for further processing.
These and other features, advantages and benefits to the present invention will become apparent from a review of the following description, when taken in view of the accompanying drawings and appended claims.